carbon cycle


Definition of carbon cycle

1 : the cycle of carbon in the earth's ecosystems in which carbon dioxide is fixed by photosynthetic organisms to form organic nutrients and is ultimately restored to the inorganic state (as by respiration, protoplasmic decay, or combustion)
2 : a cycle of thermonuclear reactions in which four hydrogen atoms synthesize into a helium atom by the catalytic action of carbon with the release of nuclear energy and which is held to be the source of most of the energy radiated by the sun and stars

Examples of carbon cycle in a Sentence

Recent Examples on the Web The big idea The ocean plays a major role in the global carbon cycle. Ken Buesseler, The Conversation, "Tiny plankton drive processes in the ocean that capture twice as much carbon as scientists thought," 21 May 2020 In what scientists call the carbon cycle, plants are like carbon dioxide vacuum cleaners, sucking it out of the air and storing it in their tissues. Dan Nosowitz, Better Homes & Gardens, "Planting a Victory Garden Can Help Fight Global Warming," 20 May 2020 Dargie entered the Democratic Republic of the Congo on Jan. 14 to study what role tropical peatlands in the Congo Basin play in the planet's carbon cycle and how these ecosystems may respond to global warming and changes in land management. NBC News, "Scientists describe 'chaos' of being stuck in the field amid coronavirus lockdowns," 1 Apr. 2020 Other themes include climate science, carbon cycles and the energy transition. The Economist, "Global warming The Economist’s coverage of climate change," 24 Apr. 2020 The planet’s global carbon cycle is a complex system in which carbon is naturally stored and exchanged among the atmosphere, land, ocean, rocks and living organisms. NBC News, "Australia wildfires unleash millions of tons of carbon dioxide," 22 Jan. 2020 Because of the way Earth's carbon cycle works, the researchers note that even a sustained 1-percent-per-year decrease in global emissions would take around a decade to have a clear impact on atmospheric measurements. Scott K. Johnson, Ars Technica, "Here’s how much global carbon emission increased this year," 5 Dec. 2019 This once-stable carbon cycle has been disrupted by our acceleration of the return of carbon to the surface by digging up and burning massive amounts of hydrocarbons: oil, gas, and coal. National Geographic, "Earth's rocks can absorb a shocking amount of carbon: here’s how," 24 Oct. 2019 Some scientists argue that the Amazon forest, a crucial part of the global carbon cycle, is at the tipping point right now. Ivana Kottasová, CNN, "Once the Amazon rainforest passes the point of no return it could be gone in decades," 10 Mar. 2020

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'carbon cycle.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of carbon cycle

1901, in the meaning defined at sense 1

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The first known use of carbon cycle was in 1901

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Cite this Entry

“Carbon cycle.” Dictionary, Merriam-Webster, Accessed 5 Aug. 2020.

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More Definitions for carbon cycle

carbon cycle


Medical Definition of carbon cycle

: the cycle of carbon in living beings in which carbon dioxide is fixed by photosynthesis to form organic nutrients and is ultimately restored to the inorganic state by respiration and protoplasmic decay

More from Merriam-Webster on carbon cycle

Rhyming Dictionary: Words that rhyme with carbon cycle Encyclopedia article about carbon cycle

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